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June 30

Copying to an iPad

How can I automatically copy a spreadsheet ('Numbers') from my Mac laptop to my iPad please? Thanks in anticipation.85.211.134.120 (talk) 08:13, 30 June 2013 (UTC)[reply]

One option is to use iTunes File Sharing to transfer your iWork documents. Another option is to save the document to iCloud, and the Mac and iPad will both automatically have the most current revision at all times. Here are setup instructions for iCloud. To use Documents in the Cloud, your Mac needs OS X 10.7.4 or newer. Nimur (talk) 15:27, 30 June 2013 (UTC)[reply]

Thanks for this but neither option works for my iPad but my wife's mini iPad gets the transfer without any action by me! What might be going on I wonder?85.211.134.120 (talk) 06:37, 1 July 2013 (UTC)[reply]

You might have to have the same iTunes account in use on the Mac and apple device for the iCloud to sync. Graeme Bartlett (talk) 10:49, 1 July 2013 (UTC)[reply]

Automatizing tasks or creating macros for web browsers

Is there something like Autohotkey but more suited towards web browser automation? Maybe JavaScript bookmarklets or Selenium? Thanks. --Immerhin (talk) 18:49, 30 June 2013 (UTC)[reply]

Greasemonkey -- Finlay McWalterჷTalk 23:17, 30 June 2013 (UTC)[reply]

July 1

Internet fax - per page charge, no monthly fee

Is there an Internet fax service that does not have a monthly charge, and charges only per page? All of the ones I found have a monthly fee, but I need this only a couple of times per year, so I don't want a monthly charge. Bubba73 ^{You talkin' to me?} 00:36, 1 July 2013 (UTC)[reply]

Check out this service. They claim no monthly charges, no hidden fees and no contracts; simply a per-page charge - exactly what you're looking for. --Yellow1996 (talk) 01:12, 1 July 2013 (UTC)[reply]

Resolved

thank you. Bubba73 ^{You talkin' to me?} 23:16, 1 July 2013 (UTC)[reply]

256th notes in MuseScore

Does anyone here have any ideas how I could "fake" beamed 256th notes (for printing, playback unnecessary but would be cool to have) in MuseScore? Double sharp (talk) 10:45, 1 July 2013 (UTC)[reply]

Ah, figured out a way:

Use a 4:2 tuplet so that they will playback correctly as 256th notes but look like 128th notes.
Use "Lines" to put a line between the first and second "256th notes".
Make the line thickness 0.55sp. It will then have the same width as a beam and you can put it in as such.

Are there any less kludgy ways? Double sharp (talk) 10:52, 1 July 2013 (UTC)[reply]

Also, is there a way to get 128th notes without using tuplets? Double sharp (talk) 10:53, 1 July 2013 (UTC)[reply]

You can rescore your music so that it does not need 1/256th notes. If you double the tempo, you can notate the same music with simpler measure division. Nimur (talk) 16:11, 1 July 2013 (UTC)[reply]

Tell that to Mozart :-) --Phil Holmes (talk) 20:01, 1 July 2013 (UTC)[reply]

That's exactly what I happen to be typesetting. ;-) Double sharp (talk) 13:56, 2 July 2013 (UTC)[reply]

I just rooted my Samsung Galaxy Victory with SuperSU, Odin, TWRP and BusyBox. How come I still can't transfer my apps to SD with AppMgr Pro III?

I got help from this video and an Android Forum post about how to root. I managed to create a successful root of the phone.

However, when I try to use AppMgr Pro III, Easy App2SD and Link2SD, they still won't let me transfer to my SD card. My SD card had 1.83 GB available, and my SD card has 29 GB available.

AppMgr Pro III still says "The device does not have a real primary external storage, or the primary external storage is emulated. Moving app to SD function cannot be supported by this device." How do I make it "change its mind" now that I've rooted?

Easy APP2SD still shows a pop-up that says "This device does not support APP2SD function." How would I change its mind?

On Link2SD, when I select all 90 movable applications, and press "Move to SD card," another popup gives: "Warning: App2SD is not supported by your device. Because your device has a primary external storage which is emulated from the internal storage. You can link the app in order to move its files to your SD card."

I don't feel sure enough about what Link2SD is asking me to do.

So since I've already rooted the phone, how else do I enable my phone and its app-moving apps to move apps to SD card and still let them operate like they would while still in the internal memory? I've hoped for a solution for a month, so thanks in advance. --70.179.161.230 (talk) 11:20, 1 July 2013 (UTC)[reply]

I don't know much about this topic, but maybe you can connect it to the computer and run the shell from there? Is it similar like the Android SDK emulator, where you can run the shell from the computer, maybe it is the same. 190.60.93.218 (talk) 16:43, 5 July 2013 (UTC)[reply]

July 2

interference to heart rate monitor

There is nothing wrong with my watch (forerunner 305). I am just wondering, will the heart rate monitor work when I am using the elliptical in the gym? It is a heart rate monitor that is worn below the chest, and pairs with the watch (it is not attached to the watch). The elliptical is about 2-2 1/2 feet from a television. — Preceding unsigned comment added by 99.146.124.35 (talk) 02:19, 2 July 2013 (UTC)[reply]

I think it's very unlikely that a TV monitor will generate strong enough electric fields to mess up a heart rate sensor that you wear on a strap that goes around your chest. Are you having problems? Looie496 (talk) 02:27, 2 July 2013 (UTC)[reply]

As to whether the sender in the chest strap will be understood by the receiver in the elliptical machine, the answer is "maybe". There's a variety of wireless protocols that such equipment uses - ANT+ seems to be the dominant (the closest there is to a standard), but other systems use other schemes, some of them proprietary. The Garmin Forerunner article suggests they all do ANT+; you'd have to see what the brand of elliptic machine uses. I have gotten a Target Fitness band working with a Life Fitness bike, but neither has markings as to how this worked. In that case, a Bluetooth-like "pairing" paradigm doesn't seem to hold, as my heartrate was shown in the two adjacent bikes too - so presumably each bike was picking the strongest radio signal, if any. Sensibly, the Life Fitness equipment would ignore the radio signal and use the signal from its contact heartbeat sensors (if there was one) - so the people riding those adjacent bikes could grab the handlebars and override the display of my heart rate with theirs. -- Finlay McWalterჷTalk 10:17, 2 July 2013 (UTC)[reply]

HP 9845C screenshots?

At the homepage about HP 9845C. There are some really nice pictures [1], [2], and at the demo [3], [4], etc. Is there any free versions of these? Electron9 (talk) 13:10, 2 July 2013 (UTC)[reply]

Wow those are pretty neat! So you mean free versions of those exact pictures? I don't think that would be possible - you would have to claim fair use. There might be similar images that are free but those, probably not. --Yellow1996 (talk) 16:10, 2 July 2013 (UTC)[reply]

⟍⟍⟍⟍⟍⟍⟍⟍⟍⟍⟍

What do we call this character? ⟍ is a redlink, as is Box (typography). 2001:18E8:2:1020:5DD6:98CF:4B3B:E815 (talk) 13:28, 2 July 2013 (UTC)[reply]

mathematical falling diagonal -- Finlay McWalterჷTalk 13:31, 2 July 2013 (UTC)[reply]

Hm. On my screen, it's a little rectangle, not the character that displays on your link; I guess I don't have the right font. I was meaning to ask: what's the "official" term for the little box that displays when you don't have the right font installed? 2001:18E8:2:1020:5DD6:98CF:4B3B:E815 (talk) 13:35, 2 July 2013 (UTC)[reply]

Exactly. More generally, if a page contains a unicode character that isn't represented by an available font, your browser will draw a placeholder box. Some browsers (e.g. Firefox) will show the hexadecimal value of the character's codepoint (27CD in this case) inside that box, so even if you can't see what the character is supposed to look like, and it's possible to search unicode info sites like the one I listed above for the character by its code. See fallback font and Unicode's "Display of Unsupported Characters" advice. It doesn't render correctly for me either, btw. -- Finlay McWalterჷTalk 13:43, 2 July 2013 (UTC)[reply]

So is the box image officially a "placeholder box", "missing glyph", a ".notdef glyph", or something else, or does it not have an official name? 2001:18E8:2:1020:5DD6:98CF:4B3B:E815 (talk) 13:47, 2 July 2013 (UTC)[reply]

Beyond those there's also "substitute character", and uncode suggests using U+FFFD � "replacement character" (see Specials (Unicode block)). -- Finlay McWalterჷTalk 13:50, 2 July 2013 (UTC)[reply]

Freezing on a Mac

I have a MacBook Pro and recently have experienced freezing when watching films with DVD player and when watching videos or listening to music in iTunes. With the music in iTunes, there is just silence for a few seconds, before the music eventually starts playing again, at the same point where it stopped. With the other two problems, the video freezes but the audio tends to continue. Can anyone suggest anything? A similar issue happened to me a while back with just iTunes and it was solved by repairing disk permissions but that hasn't helped this time. Thanks. meromorphic [talk to me] 20:43, 2 July 2013 (UTC)[reply]

Have you tried reinstalling your video drivers? --Yellow1996 (talk) 20:34, 3 July 2013 (UTC)[reply]

You really don't do that on a Mac ;-). Check if the Activity Monitor shows some unusual activity. Sometimes a rogue process uses too much system resources. --Stephan Schulz (talk) 20:44, 3 July 2013 (UTC)[reply]

Ah - I see! I was actually going to affix "I was hoping that an actual Mac user would respond, but..." to my answer; and luckily for the OP, one has! ;) --Yellow1996 (talk) 21:10, 3 July 2013 (UTC)[reply]

Well, I'm more of a UNIX head, but PowerBooks/MacBooks have for a while been the best UNIX laptops one could buy. Not modern Ultrabooks with Ubuntu come close, but not yet close enough... --Stephan Schulz (talk) 21:55, 3 July 2013 (UTC)[reply]

How much RAM do you have? How much free space on your startup drive? Are you running a lot of other programs at the same time? It kinda sounds like your system is thrashing. --Navstar (talk) 19:36, 5 July 2013 (UTC)[reply]

July 3

What are these computer games?

First was on an Atari, I think. You play this guy whose spaceship crashes on a planet. The very first scene involves swimming out of your wrecked spaceship before some tentacles grab you. Then you are up on the shore of the lake. You have to move fast or the tentacles will reach out of the water behind you and drag you back into the water. There are some kind of horrible snake/worm things in this first scene as well.

The second was on the Amiga. It is a vertical scrolling platform game. I think it is set on Mars and you play one of two little creatures who are searching for water. There are signs everywhere saying "H2O".

Any ideas? Horatio Snickers (talk) 10:59, 3 July 2013 (UTC)[reply]

I'm amazed that I'm stumped for the first one because I am really familiar with Atari games... and is the second one Flood? --Yellow1996 (talk) 17:54, 3 July 2013 (UTC)[reply]

The first one: Another World? (I had the Press Start for Game Over trope open some weeks ago, and searching for "tentacle" threw it up.) - ¡Ouch! (^{hurt me} / _{more pain}) 08:00, 4 July 2013 (UTC)[reply]

Another World - that's the one! I'm pretty sure the first one wasn't Flood, though. It doesn't look similar to me. If it helps, I think the version I played was a demo given away for free on an Amiga magazine but I have no idea when. Thanks! Horatio Snickers (talk) 15:28, 4 July 2013 (UTC)[reply]

Every Amiga game ever released - should be on there somewhere! :) Do you remember anything about the title of the second game? That might make finding it a lot easier than sifting through all those lists (they're in alphabetical order); either way, it's somewhere on that site. --Yellow1996 (talk) 16:30, 4 July 2013 (UTC)[reply]

I've got it! Flip-it & Magnose: Water Carriers from Mars, apparently! Had a look at that site but there's a lot on there - did a search for "amiga mars water" in the end and it popped up. Thanks for all your help! Horatio Snickers (talk) 10:26, 5 July 2013 (UTC)[reply]

You're very welcome! I'm glad you found it! :) --Yellow1996 (talk) 17:39, 5 July 2013 (UTC)[reply]

Searching in Windows Explorer

Is it possible to limit searches in Windows Explorer (on Win7) to exact file-name matches? By default when searching for, say, file.ext, it seems to find anything that matches *file*.*ext* Rojomoke (talk) 16:16, 3 July 2013 (UTC)[reply]

Never mind. Double quotes are what I needed. Rojomoke (talk) 16:27, 3 July 2013 (UTC)[reply]

Speaking on the same subject, is there any way to get Windows 7's search to behave/imitate like Windows XP's search function? I find XP's to be much more powerful and requires little/no confusing syntax (since 7's is all in one search box). -- 140.202.10.134 (talk) 16:43, 3 July 2013 (UTC)[reply]

This tutorial may be of some help. --Yellow1996 (talk) 17:48, 3 July 2013 (UTC)[reply]

In my experience, the Win7 search is unreliable, even if you follow the above tutorial. I either use Super Finder XT (if I want a GUI) or Grep under Cygwin (seeing as I'm from a Unix background). --TrogWoolley (talk) 22:02, 3 July 2013 (UTC)[reply]

Need a complicated, but really cheap site.

A non-profit is looking for someone to create a rather complicated web site. My guess is that it would take an experienced programmer at least 3 months to create it. As the budget is really small (a few thousand dollars at most) I was wondering if there are reliable websites to find freelancers directly at "Bangalore rates", without having to pay for managers, etc. I could do the managing, but I don't have 3 months holiday at hand.. Any ideas? Joepnl (talk) 23:04, 3 July 2013 (UTC)[reply]

You can always have a look at guru.com - my brother really swears by them, but I'm rather skeptical, personally. I expect that any money you try to save by going the cheap route, you'll have to pay for later in trouble, and most likely it will require quite a bit of managing. 3 months to create a website sounds like a pretty damn complicated website, too - do you have any reasoning behind this estimate or did you just ballpark it? 64.201.173.145 (talk) 02:33, 4 July 2013 (UTC)[reply]

Perhaps if you can describe the complexities they want, we can suggest simpler and more economical ways of accomplishing the same thing. For example: Do they want a zoomable, rotating Earth as a way to zoom in to any of their sites ? How about a non-zoomable, pickable flat map instead ? StuRat (talk) 08:10, 4 July 2013 (UTC)[reply]

Thanks both, I'll have a look at guru.com. It's not technically complicated, but there are just al lot of tables, screens, buttons, etc. Joepnl (talk) 13:26, 4 July 2013 (UTC)[reply]

Downloading and editing portions of a NSA video on polygraphing

There is an NSA-produced video on the polygraphing process:

While an NSA-produced video is public domain, it also uses very short excerpts of footage from copyrighted TV shows: Meet the Parents and The Simpsons So, does this mean, for it to be posted on the Commons, the footage of the TV shows has to be cut out (I assume yes, but just making sure)? How should I download the video and do the editing? WhisperToMe (talk) 23:36, 3 July 2013 (UTC)[reply]

IANAL, but I would assume your notion of having to cut out the copyrighted material would be correct. As for downloading the videos, I have gotten great use out of DownloadHelper for Firefox. For the editing (the cutting-out of the copyrighted material) any free movie making/editing software should do (though Windows Movie Maker generally doesn't play nice with the types of files you'll get from DownloadHelper and similar addons - you'll need a converter.) --Yellow1996 (talk) 16:38, 4 July 2013 (UTC)[reply]

July 4

Memory not entirely recognized by laptop

I have an eMachines E627 laptop, and I have two 2GB memory cards installed (which, according to the technical specifications of the system, is the maximum amount of memory permissible for this model). However, it seems that only the memory installed in the inner slot gets recognized by the system, whereas the memory installed in the outer slot does not. I experimented with the system and determined that each individual memory card works fine when installed in the inner slot. Is this problem common? How can I get the system to recognize all 4GB of memory installed? 24.47.141.254 (talk) 02:43, 4 July 2013 (UTC)[reply]

What operating system are you using, and how are you determining that it can't see all the memory? RudolfRed (talk) 03:04, 4 July 2013 (UTC)[reply]

Also, have you checked if all 4GB is visible to the BIOS? WegianWarrior (talk) 03:49, 4 July 2013 (UTC)[reply]

I am using Windows 7. When I run setup at the beginning, BIOS shows 2048 MB of memory (instead of the expected 4096 MB), and the "System" function from my Control Panel shows 2.00 GB of memory (not 4.00 GB). During my experiments, I tried inserting one memory card into the outer slot and leaving the inner slot empty, and surely enough, the screen did not display anything when I powered up. 24.47.141.254 (talk) 05:08, 4 July 2013 (UTC)[reply]

If your BIOS does not recognize more than 2GB, there is no way the OS will be able to see it either. Not sure how to fix though, sorry. WegianWarrior (talk) 06:49, 4 July 2013 (UTC)[reply]

Try booting with RAM in the outer slot only. If it doesn't boot, the slot is probably broken. Also, try putting smaller modules in each slot or just the inner slot if you have any available. -- BenRG 23:31, 4 July 2013 (UTC)

I would go to www.crucial.com with that computer and have it scan your computer, and let it tell you how much RAM it sees and how much RAM it can take. I looked for your model there but I didn't find it. But I've found Crucial.com to be reliable about memory. Bubba73 ^{You talkin' to me?} 03:29, 5 July 2013 (UTC)[reply]

Or get a program like Speccy: http://www.piriform.com/speccy - it tells you that information. Bubba73 ^{You talkin' to me?} 03:32, 5 July 2013 (UTC)[reply]

Calculating Pearson correlation coefficient with Python

def pearson_correlation(a,b): # Python 3
    if len(a)!=len(b):
        raise ValueError('samples are of unequal size')
    mean_a=mean_b=0
    for i,j in zip(a,b):
        mean_a+=i
        mean_b+=j
    mean_a,mean_b=mean_a/len(a),mean_b/len(b)
    x=y=z=0
    for i,j in zip(a,b):
        x+=(i-mean_a)*(j-mean_b)
    for i in a:
        y+=(i-mean_a)**2
    for j in b:
        z+=(j-mean_b)**2
    return x/(y*z)**(1/2)

This function takes two samples as two lists and returns the Pearson correlation coefficient of them. Is there any thing wrong with it? Czech is Cyrillized (talk) 02:56, 4 July 2013 (UTC)[reply]

I see some possible problems:

1. The usual way to make multiple assignments on one line in Python is

mean_a, mean_b = 0,0

I think an expression like

mean_a = mean_b = 0

is assigning mean_a to the result of the expression "mean_b = 0" - although in this case that could be 0 anyway, so this might make no difference.

2. Be very careful with integer division in Python. One of the oddities of Python is that any arithmetic expression that includes only integers returns an integer value - so 1/2 will return 0, whereas 1./2 will return 0.5 because 1. is a float not an int. So your final line

return x/(y*z)**(1/2)

will always return 1 (I think) because the value of 1/2 is 0. You could try

return (float(x)/(y*z))**(0.5)

or you could use the sqrt function, but you have to import that from the math module. And if your lists a and b only contain integer values, there could be a similar integer division problem when you are calculating mean_a and mean_b. A good rule of thumb is that wherever you have a division expression that you expect to return a non-integer value, convert the numerator or denominator to a float to force the result to be a float.

3. Not a problem as such, but the loop where you sum the values in lists a and b is not necessary because Python has a built in sum function that returns the sum of values in a list.

Gandalf61 (talk) 11:40, 4 July 2013 (UTC)[reply]

If I understand your mean_a, mean_b calculations properly, and taking into account Gandalf61's wizardly advice about floats, the calculation of those two can be simplified to:

  mean_a = float(sum(a))/len(a)
  mean_b = float(sum(b))/len(b)

turning 5 lines into two (and to my mind being much clearer). edit yeah, I didn't read Gandalf's last point before posting.-- Finlay McWalterჷTalk 12:48, 4 July 2013 (UTC)[reply]

You can also change those calculations for x, y, z into sums on list comprehensions, like

x= sum([(i-mean_a)*(j-mean_b) for i,j in zip(a,b)])

- although that's not such an obviously clearer piece of code. -- Finlay McWalterჷTalk 13:01, 4 July 2013 (UTC)[reply]

Assignment isn't an expression in Python; x = y = 0 works by special dispensation, not because of expression rules. So it's evidently an officially endorsed way of doing multiple assignment (and it's pretty common in Python code).
There's a near universal convention of putting spaces after commas in Python code. You should follow it for readability's sake. It's also good practice to put spaces around infix operators.
In Python 3.x, the / operator returns a floating-point result even if the arguments are integers, and // does integer division (as described in PEP 238). Since Python 2.2 (released in 2001), you can write from __future__ import division at the top and then just say sum(a) / len(a), etc. This is a good idea for forward compatibility reasons.
Finlay McWalter's sum([...]) can be shortened to sum(...) as of Python 2.4 (released in 2004).

-- BenRG 23:27, 4 July 2013 (UTC)

Why cant Graphics processing units keep up with Central processing units?

"Top" GPUs like Tahiti XT in AMD "Radeon 7970" and "7990" series Videocards or as GPU from Nvidia (GK110) in "GeForce GTX 780" or "Titan" labled Videocards work on a frequencies of 900-1000 MHz. Same time "TOP" CPUs from Intel like "core i7 3770K" or "core i7 4770K" run at 3500 MHz and additionally are known to overclock to near 5000 MHz as are CPU from AMD like "AMD FX-4350" starting even from 4200 MHz. Same with "big professional" brands like SPARC T5 (3600 MHz). Why is it that customers willing to pay beyond $ 1000 for a Nvidia "Titan" Videocard only get a 900 MHz GPU and one buying a 3500-4500 MHz CPU like "core i7 4770K" only has to pay $ 300. Also why exactly are GPUs not also clock atleast near with maybe 3000 MHz? --Kharon (talk) 07:18, 4 July 2013 (UTC)[reply]

Roughly, because "clock speed" is a really bad measure of performance. See Megahertz myth. Graphics cards do different things per clock, and they can use massive parallelism. In fact, GPUs are much ahead of CPUs in pure processing power, and there is an increasing trend to tap into that performance for general purpose computing. See General-purpose computing on graphics processing units. The high end Radeon Sky 900 is rated at nearly 6 TeraFLOPS, while the best multi-core i7 CPUs are stuck more than an order of magnitude behind that. --Stephan Schulz (talk) 08:29, 4 July 2013 (UTC)[reply]

Nonetheless it's an interesting question why GPUs tend to be clocked slower than CPUs. (I don't know the answer.) -- BenRG 23:29, 4 July 2013 (UTC)

Because clock speed is not the limiting factor for most GPU workloads. Unlike a typical CPU workload, there is much lower temporal locality in a GPU's operations. The little temporal locality that does exist already gets exploited by using a specialized pipeline. So, with little data reuse, the data transfer rate dominates performance. A very small parallel work-load, say four 32-bit integers wide, requires 128 bits per transaction. A fully-utilized GPU will therefore input and output 128 bits per clock - or, at 1 GHz, will require 256 GBits/sec of available bus bandwidth. No system-bus in the world can sustain that data-rate, at least not in 2013. So, clocking the GPU faster means that the GPU is under-utilized, most of the time. This is unlike the CPU, where a small amount of data is reused over many computer instruction cycles, taking full advantage of the processor cache.

If you look at the structure of a modern GPGPU, you will see that the best effort solution to this problem is to allow the kernel programmer to manage the GPU cache memory in very customized way. When I worked on the Tesla S1070, there were some 16 kilobytes of what you might handwavingly call the L1 cache - and using the CUDA extension to the C programming language, the programmer allocated that memory to each processing kernel (i.e. to each processing unit). Even with this kind of fine-grained control, it was uncommon to get as high as, say, 16 instructions per word for a typical massive parallel calculation. Inevitably, the cache was never very useful, and memory transfer time from main GPU RAM and system RAM overwhelmingly dominated the total process execution time. My program, calculating the wave equation, would burst for a couple microseconds, cranking along at an instantaneous rate of a few gigaflops at a time... and then stall for hundreds of milliseconds waiting to copy the result back to system memory, and copy in new work. Getting "lots of flops" isn't too hard if you have a thousand cores running at a mere 1 GHz! One billion instructions require just one millisecond of work! And our 960-core S1070 is now four-year-old technology - today's GPUs have more cores! Keeping the GPU busy for more than one millisecond out of each second - now that is still a challenge!

In other words, even at a mere 1 GHz, the GPU is still too fast for the memory and system to keep up. Clocking it faster burns power and accomplishes no extra work - the GPU will simply be spending more time waiting in a pipeline bubble executing no-op instructions. You can read about even more recent GPGPU architecture details at Nvidia's website: http://nvidia.com/cuda . Nimur (talk) 01:54, 5 July 2013 (UTC)[reply]

How does solar model works

Do all scientists use computer simulations and solar models to calculate future for the sun or only certain groups of astrophysics does that. Because I have problem think concrete details that is why I thought [5] when scientist do solar model all the variables are well-written. I cannot tell when they guess on the variable they don't know. When astrophysics create solar model do they have to fill out the data entry they are require to fill out all the variables? How can they guess on certain variables if they have to fill in variables on the solar model? If they don't know they can just leave that entry blank. Do solar model require all variables to be fill out in order to run the simulation? Can these two documents I linked above have alot of errors, I can't tell because I am not a concrete thinker--69.233.254.115 (talk) 20:20, 4 July 2013 (UTC)[reply]

Both articles are not based on the very latest data; one is from 1993 and the other is from 1997. The intended audience is also very different: The first is published in ApJ, a very well respected scientific journal in which astrophysicists publish the results of their research, and uses language and assumes knowledge that other astrophysicists would be familiar with. The second has a more popularist style suitable for being presented in a lecture to university undergraduates and the wider public at an observatory.

As I found out at university, there is no one standard computer model of stellar evolution and each model is (or at least our model was) wildly sensitive to the input conditions. For most models some data is well known, some has pretty good estimates (within a small range of values), and other data can be widely different. However, most computer models will treat a blank value as zero, instead of "I don't know", unless it has specifically been written to account for this. While zero pressure in space isn't too bad an estimate, zero kelvin at the star's surface is a really bad estimate. Astronaut (talk) 18:29, 5 July 2013 (UTC)[reply]

Does how old the articles are really matters on how accurate the information will be? How will newer data make older data more accurate. How will people be able to study things more accurate just 16-20 years timeframe? Is it short time frame phases only 10-50 million years needs deeper studies. So some models can estimate well, and others can range widely. What happens if you write "I don't know" on input entries? in astronomical time scale 100 million years really is only a small fraction of timescale right.--69.233.254.115 (talk) 20:12, 5 July 2013 (UTC)[reply]

July 5

mouse malfunction?

A lot of times lately an a browser when I click to go back, it goes back two pages. I'm wondering if the mouse is sometimes sending two "clicks" instead of one. Is there a way to test the functions of a mouse? Bubba73 ^{You talkin' to me?} 14:50, 5 July 2013 (UTC)[reply]

Try a paint program; if it's somehow generating two clicks the paint program would show two blobs and not one. 87.112.233.132 (talk) 14:58, 5 July 2013 (UTC)[reply]

I don't have a paint program loaded, as far as I know. Bubba73 ^{You talkin' to me?} 15:12, 5 July 2013 (UTC)[reply]

try http://api.jquery.com/dblclick/ On the "demo", when you double click it changes color.190.60.93.218 (talk) 16:25, 5 July 2013 (UTC)[reply]

Or try a Google search: online mouse click counter. There are even games about how many times you can click. PrimeHunter (talk) 16:32, 5 July 2013 (UTC)[reply]

But that doesn't tells if he has clicked or doubleclicked, also on Windows at Control Panel>Mouse you can modify the time limit on where to send a doubleclick. 190.60.93.218 (talk) 16:41, 5 July 2013 (UTC)[reply]

OK, I tried that link above and sometimes it is doing a double click. Then I went to the control panel/mouse and set the double-click speed all the way "fast". I clicked slowly, and sometimes it took it as a double click, about one out of 5 to 15 times. So it must be either the mouse going bad (it is a good Logitec but several years old) or maybe some malicious software. Bubba73 ^{You talkin' to me?} 16:57, 5 July 2013 (UTC)[reply]

This seems to suggest it might be a messed up microswitch; though this appears to be a common problem amongst Logitec users. Try plugging it into a different PC and see if the problem persists. Though you may have to end up replacing it. --Yellow1996 (talk) 17:45, 5 July 2013 (UTC)[reply]

Can computers/programs/algorithms/functions explain or create other functions or algorithms?

Is it possible that computers can create or explain functions? Like a normal human (programmer) does it all the time, Humans can do many things like from writing, drawing (abstract), etc... How can a computer do it? 190.60.93.218 (talk) 16:19, 5 July 2013 (UTC)[reply]

Synthesizing a new algorithm is a common process. This is sometimes lumped under the blanket-term polymorphic code - program code that modifies itself. There are many approaches. Among the most common techniques are genetic algorithms that try tiny modifications to a known, working algorithm; and gradually, the program evolves into an entirely new algorithm. The hard problem is not creating new executable programs - even a simple pseudorandom number-generator can easily spit out a random series of instructions! The difficult challenge is determining whether the new algorithm has accomplished a useful task. That problem is related to the halting problem; and it is also related to the discipline of optimization and classification. Some-how, the master control program needs to determine whether a newly-created algorithm falls into the category of "working" or "not working," which is a stickier problem than it seems at first glance.

"Explaining" an algorithm - in a way that a human can easily understand - is a challenge of natural language processing and semantic processing. This is a very new field - it is on the edge of very new research problems - so there are not really any currently-available tools that work out-of-the-box. Nimur (talk) 16:50, 5 July 2013 (UTC)[reply]

Note that "explain functions" is what a large part of machine learning is concerned with, i.e. finding a model that reproduces a given samples as exactly as possible. See e.g. computational learning theory for the more theoretical part of this. --Stephan Schulz (talk) 18:45, 5 July 2013 (UTC)[reply]

The purpose of Bitcoin mining?

Can someone explain to me the purpose of Bitcoin mining? It's my understanding it's just hashing busywork. Are the hashes that mining generates have any purpose? --Navstar (talk) 19:26, 5 July 2013 (UTC)[reply]